Currently, antenna-integrated radios exist. These are devices that integrate antennas with remote radio heads (RRHs). A remote radio head includes power amplifiers (PAs), filters, antennas, and a digital interface. Radio signals are received at the antenna, translated into digital format at the integrated RRH, and sent over a CPRI interface to a baseband unit located separate from the antenna-integrated radio.
Also known in the art is multiple-in, multiple out (MIMO). MIMO provides increased data rates, and uses multiple antennas to do so. For an example of a remote radio head, see U.S. Pat. App. No. US20110158081, hereby incorporated by reference in its entirety.
A 2×2 MIMO remote radio head typically includes the following components. A common public radio interface (CPRI) interface may be provided from a baseband unit, which handles processing of all radio signals, into a digital board. The digital board may be coupled to a software-defined radio (SDR). The software defined radio may provide two transmit and two receive channels, with the transmit channels being coupled to power amplifiers (PAs) and the receive channels being coupled to low-noise amplifiers (LNAs). The channels may then be coupled to one or more appropriate filters. The filters may be connected to the antennas via connectors.